[Pt(Met)(DMSO)Cl][PtCl3(DMSO)] complex, where Met corresponds to metformin drug, was synthesized and characterized using UV–visible spectroscopic, FT-IR spectroscopic, elemental analysis, conductivity measurements and X-ray single-crystal diffraction techniques. The binding affinity of the platinum complex with DNA was explored by adopting competitive fluorescence spectroscopy, the effect of ionic strength, and viscosity measurements. The results revealed that the platinum complex interacts with DNA via a groove binding mode. The in vitro cytotoxic property of the platinum complex was evaluated in HCT-116 (human colon cancer cells). Compared with gefitinib, which is a common anticancer drug and has an IC50 value of 9.33 μg/mL on the HCT- 116 cells, the IC50 value of the platinum complex synthesized in this work is 6.35 μg/mL. Thus, the present platinum complex can be potentially used for cancer chemotherapy. The nature of metal-ligand bonds in the complexes was investigated using energy decomposition analyses (EDA). The results of EDA calculations at BP86- D3/TZ2P(ZORA) level of theory confirmed that the contribution of the term ΔEelstat in ΔEint value is about 60–62 %, indicating that in all complexes the metal-ligand bonds are mostly electrostatic in nature. Furthermore, molecular docking studies were carried out using DNA structure (PDB ID: 1BNA) to clarify the molecular affinity between various optimized analogs of platinum complexes and DNA. The results show that [Pt (Met)Cl(DMSO)] can form two hydrogen bonds with DNA, while other analogs form only one hydrogen bond with DNA.
